Minutes of the E895 meeting Graduate Chemistry Rm 403, SUNY Stony Brook Monday 9/11/95 Attending: MG - Mark Gilkes JR - Juan Romero JA - John Alexander RL - Roy Lacey PC - Paul Chung SG - Steve Gushue AJ - N. Ajitanand EL - Erwan LeBras TPC: ==== MG - All stick power cables are connected and routed out of the clean room and over the boom arm. Joe S. has arranged for new strain relief on the distal end of the boom, and a new support bracket on the front-mounted TPC cable tray (on the right side looking into the re-entrant, where most of the cable weight is). The new pieces were installed late last week. The cabling team of Heng Liu, Paul Chung, Erwan LeBras and myself finished the job started by Daniel Cebra before he returned to Davis. We have kept the length of the cables as uniform as possible over the run from the TPC to the power supplies, to reduce strain when the detector is moved. MG - HL, PC, EL and I made a tour of the MPS area this morning to discuss the rest of our cabling needs. Daniel has connected the Bitbus and clock/ trigger cables at the TPC end, and it remains for us to string them to the control room. The stick power cables have to be connected to the power supplies. We intend to return the LeCroy 1440 to the MPS floor, connect the anode SHV cables, and we may have to make a cable to return the alarm signal to the control room. Once stick power and Bitbus are connected, we can communicate with the sticks over Bitbus. SG - It appears that Larry has installed 220 VAC in the control room, so we could leave the LeCroy there. MG - This is another possibility. But I should check to see whether we have the long SHV's that would be required in order to connect the anodes with the power supply in the control room. SG - Bob Hackenburg goes on vacation till the first of October. I'd like to get the situation resolved regarding the liquid nitrogen. Trailers with tanks on them are available. This would be preferable to the Dewars, which have to be changed more often. TARGET ASSEMBLY: ================ MG - I am now leaning toward a design in which there is only one target, which is drawn out of the re-entrant volume in order to be replaced. This is an easier scheme, considering our space constraints with the ST after- target scintillator and a possible 4-inch beam pipe in the vicinity. We'll have room for a bigger target. SG - Also, not as much concern about the environment around the target, which is potentially different if you have adjacent but dissimilar targets on each side of a given target on a wheel, for instance. You could get different background interactions for one target versus another. MG - We would support the target off the re-entrant flange, and remove it by tilting it downward and drawing the shaft out through the bearing. SG - If there is enough adjustment along the beam direction, this might also work for E910. AJ - But it's convenient to have many targets available in the early part of the experiment, when we're changing targets often. SG - Mostly one wants a given target in, then out. MG - I like the idea of exactly the same environment for each target. It may come down to space constraints. It's easy to obscure a laser port. MG - What about safety issues if the magnet is on ? Can we work around or inside it ? SG - The operations manual for the magnet is not clear on this point, but it sounds like it's not recommended to have people do this. We should get this settled. MUSIC: ====== JR - Jerry left Friday after spending four weeks. The pace of our work was a combination of periods of waiting followed by a lot of activity. Last week, everything came together. The object was to return MUSIC to its original support. Before this could be done, the support had to be shortened for the new beam height. This has now been done at last. We have replaced the field cages and tested them under nitrogen over the last weekend. Everything looks good. Heng has been very helpful - we could not have replaced the cages without him. JR - Joe Scaduto is working on the endcap stands. The endcaps are independent of the main tank, and they need to be attached if we are to pump down the detector and keep it clean. MG has offered to take responsibility for the endcaps, and for pumping the detector down. RL - Is the gas system operational ? JR - Nitrogen, yes. The P10 will have to wait until October when the TPC gas system is in place. JR - Most cold tests (without signals) check out fine. All preamps are OK. We only have half of the shapers, but the rest will come eventually. However, no progress has been made on the DAQ. Also we'll have to wait for P10 before we can see the signal from the alpha sources inside the field cages. AJ - Any other tests ? JR - Well, we've completed the preamp tests, tests of the existing shapers and the field cage HV test. We can't test the flash ADCs till we have the DAQ. We blew a fuse when powering up the FADC - two of the fuses may have been switched. JR - The fact that the field cages held voltage for half an hour is a good sign. We were not expecting them to perform so well this early. The current readings agree with past experience. JR - Jerry has prepared a WWW page on the current status of MUSIC. See http://altair.ucdavis.edu/~jerry.music.html JR - If we can get the endcaps in place before I leave, we could pump down. Mark will handle this after I leave. RL - Do you recirculate P10 ? JR - No, we just vent. RL - Recirculation would really reduce the cost of the gas. SG - You have to have a tight system, or you recirculate impurities. MG - Erwan and I will look after MUSIC in the interim, before the experts return. Prepared by: Mark Gilkes